The invention relates to cylinders for use in a machine handling continuous lengths of web material and more especially but not exclusively to an impression cylinder for a rotogravure printing press, comprising a tubular casing to be supported by respective bearings at the sides of the machine and which contains a non-rotary spindle having an external diameter which is smaller than the internal diameter of the casing and being connected with the casing by way of at least one support bearing which is symmetrically placed in relation to the length of the cylinder and is coaxial in relation to it, such support bearing furthermore spanning an annular space which is between the spindle and the casing and serves to contain an oil filling which at least partly fills the space.
A cylinder having these features has been previously proposed in the German Auslegeschrift specification No. 3,114,731, whose oil filling was however to be stationary and was only intended to ensure equalisation of temperature along the length of the cylinder and prevent local hot spots on its casing. Cooling of the cylinder casing and thus of the covering on it would not have been possible with such a system. In the previously proposed arrangement there was a limitation of the permissible speed of rotation of the cylinder to a value very much lower than the speed of 50,000 revolutions per hour as required for modern rotogravure presses, this being because high speeds of revolution led to considerable internal friction in the core of the rubber cover of the cylinder above the temperature limit specified therefor so that there was an unfavorable effect on the length of life of the rubber cover.